Another dodgy green claim that I've looked at from time to time is the environmental and economic benefits of recycling.
In Roger Harrabin's latest piece, we hear once again about the resources expended on recycling, and once again we hear that there is little or no market for all the product of all this spending.
Shifting priorities on waste presents many challenges. Many councils have moved to co-mingled waste in which domestic waste is sent to recycling centres where items are separated by air-blowing machines like giant tumble-driers.
The system is cheaper than separation by hand, but can leave fragments of waste in the wrong recycling streams - glass in paper is a particular problem.
Another challenge is developing markets for recycled materials. The UK waste industry is fragmented with different councils adopting very different approaches.
Environmentalists do love waste don't they?